An investigation on the impact of blue and green spatial pattern alterations on the urban thermal environment: A case study of Shanghai

Consistent urbanization and global warming escalates the summer temperatures of the urban, significantly impacting daily lives and endangering well-being. It is difficult to balance urban construction and increasing the blue-green space. Hence, understanding the impact of changes in the blue-green spatial patterns in different spaces on the urban thermal environment is beneficial to the rational layout of urban patterns. Drawing from the case study of Shanghai, by employing bivariate spatial autocorrelation and multiscale geographically weighted regression, the spatial interplay between changes in the blue-green spatial distribution and modifications in land surface temperature grades is scrutinized, thus unraveling the underlying mechanisms of their mutual influence. The findings reveal the following: (1) The transformation of the blue-green spatial pattern exhibited substantial discrepancies between the northern and southern sectors. (2) The alteration of the thermal environment in Shanghai varies significantly spatially and is characterized by a decrease in temperature grade in the southwestern suburbs, an increase in the east, and almost no change in the central urban region. (3) Furthermore, the correlation between the extent of the change in the blue-green spatial pattern and the change in land surface temperature manifested spatial unevenness. (4) Finally, the mechanism underlying the changes of alterations in the blue-green spatial pattern on the thermal environment of the city emanates primarily from the influence of heat exchange areas. The spatial instability of the influence of blue-green spatial pattern on land surface temperature can provide implications for urban planners.